use consistent tomogram centre in setProjectionMatrix - #1353
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TomogramSet::loadTomogramsetsTomogram::centrewith floating point division (out.centre = d3Vector(out.w0/2.0, out.h0/2.0, out.d0/2.0)), whichParticleSet::getPositionadds to convertrlnCenteredCoordinate*Angstinto decentred tomogram pixels.Tomogram::setProjectionMatrixrecomputes the same quantity with integer division,specimen_center((double)int(w0/2), ...), for thes0translation. The two agree for even tomogram dimensions and differ by half a pixel for odd ones, leaving a residual ofcentre_float - centre_intof 0.5 px per odd axis inprojectionMatrices[f] * pos.This reaches subtomogram extraction through
TomoExtraction::extractAt2D_Fourier, which projects the absolute 3D position to locate the crop centre in each tilt image. Odd tomogram dimensions are not prevented and can occur in practice. Supersedes #1286, which proposed the same change framed as a floating point accuracy improvement and was closed on the grounds that integer division is intentional for even-sized boxes. That applies to particle box sizes, which RELION constrains to be even; it does not apply to tomogram dimensions, which are unconstrained. See also #1284.